April 9, 2019
Research spearheaded by a lecturer at the University of Huddersfield in West Yorkshire, England, has found that pregnant women can significantly reduce the risk of a stillbirth by sleeping on their left or right sides—but not on their backs, because that position reduces blood flow to the fetus.
In the United Kingdom, there are about nine stillbirths a day—which works out to about one in every 225 births. The findings of the new study, published on The Lancet’s EClinicalMedicine website, now will be incorporated by the NHS into its Saving Babies’ Lives advisory “care bundle” for pregnant women.
Dr. Tomasina Stacey , a reader of Midwifery Practice at the University of Huddersfield, carried out her doctoral research while based at University of Auckland in New Zealand—investigating whether sleeping position could be a factor in causing stillbirths. She concluded that the small proportion of pregnant women who sleep on their backs did run a higher risk of losing their babies, because the weight of the uterus can reduce blood flow to the baby.
Her findings from this initial exploratory study were described in an article published by the British Medical Journal.
And since Stacey’s study was the first to report maternal sleep-related practices as risk factors for stillbirth, it triggered further research—culminating in a large-scale international project that gathered data from 851 bereaved mothers and 2,257 healthy pregnant women in New Zealand, the UK, Australia, and the USA.
The chief finding: After the 28th week of pregnancy, “back sleeping” increases the risk of stillbirth by 2.6 times. This heightened risk occurred regardless of the other known risk factors for stillbirth.
The NHS care bundle states: “In later pregnancy (after 28 weeks), it is safer to go to sleep on your side than on your back”. It advises practitioners to “encourage women to settle on their side when they go to sleep or have a day-time nap, rather than on their back. A woman who wakes up on her back shouldn’t worry, but should settle to sleep again her side.”
Sleeping position remains an important strand of Dr. Stacey’s research. It originated when she and a team at the University of Auckland—including her PhD supervisor Professor Lesley McCowan—were investigating the relatively high rates of stillbirth in New Zealand.
“We decided to look at a range of modifiable risk factors and this was one of them,” said Dr Stacey, further noting, “The next phase is to ensure that there is consistent advice from healthcare professionals and we will be looking to see if there are ways of helping to support women to sleep in the side position.
“Only a small proportion of women will be affected,” continued Dr Stacey. “But the studies that we [conducted] following the first findings suggested that women were quite happy to change their going to sleep position if it was better for their babies.”
Research contact: T.Stacey@hud.ac.uk